The newer engines place increased demands on the lubricants to be employed. In the past a number of different additives have been added to lubricating oils to improve such properties as viscosity-index and dispersancy. One such additive added to lubricating oils to improve viscosity index is a two-block copolymer having the general configuration A-B where A is styrene and B is hydrogenated isoprene. See generally U.S. Pat. No. 3,763,044 and U.S. Pat. No. 3,772,196. Significant reductions in cost can be made by employing a single additive that improves a number of lubricant properties. However, in attempting to improve more than a single lubricant property, care must be taken in not causing the deterioration of other properties. For example, by employing an oxidation step to attach polar groups to the polymer backbone in U.S. Pat. No. 3,864,268, the patentees have reduced lubricant stability by introducing sites for oxidative attack.